CD4(-LYMPHOCYTOPENIA IN LONG-TERM SURVIVORS FOLLOWING INTENSIVE CHEMOTHERAPY IN CHILDHOOD CANCERS() T)

Background. It is generally believed the effects of short intensive co urses of therapy are rapidly reversible in childhood cancers, and immu nologic function following years of maintenance treatment with chemoth erapy usually returns to normal by 6 months or less when treatment is terminated. However, we previously demonstrated that dysregulation of immunoglobulins, especially IgD, was observed in long-term survivors f ollowing intensive chemotherapy in cancer patients. With regard to cel lular immunity, investigators reported that antineoplastic chemotherap y significantly reduces the number of CD4(+) T-lymphocytes, and produc tion of newly developing CD4(+) T-lymphocytes was inversely related to the patients' age. However, the incidence of CD4(+) lymphocytopenia i n long-term survivors of childhood cancers is not known. Procedure. He re, we report the flow cytometric analysis of peripheral blood from lo ngterm survivors who continue complete remission off chemotherapy for more than 5 years. Results. Six out of 74 long-term survivors (8.1%), showed low CD4(+) T-lymphocyte count (<300/mm(3)). Three of six patien ts showed continued CD4(+) T-lymphocytopenia over a year. In spite of the persistent low levels of CD4(+) T cells, these three patients were not susceptible to severe infections. Comment. Intriguingly, in patie nts with CD4(+) T-lymphocytopenia there has been a tendency toward inc reased numbers of natural killer cells or gamma delta T cells that may be operating as a thymus-independent compensatory mechanism to defend the hosts. (C) 1998 Wiley-Liss, Inc.